Staircase



FIG. 1 is a perspective view of a staircase incorporating my design and arranged back-to-back;

FIG. 2 is a perspective view of the staircase;

FIG. 3 is a side elevation view thereof, the opposite side being identical thereto;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a rear elevation view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

Broken lines in the drawings are for illustrative purposes only and are not part of the claimed design. 

The ornametnal design for a staircase, as shown and described. 